Buggy code:
public class ConcreteAspectCodeGen { private static final String [ ] EMPTY_STRINGS = new String [ 0 ] ; private static final Type [ ] EMPTY_TYPES = new Type [ 0 ] ; private final ConcreteAspect m_concreteAspect ; private final World m_world ; private boolean m_isValid = false ; private ResolvedType m_parent ; private PerClause m_perClause ; ConcreteAspectCodeGen ( Definition . ConcreteAspect concreteAspect , World world ) { } public boolean validate ( ) { if ( ! ( ( m_world ) instanceof BcelWorld ) ) { reportError ( "Internal<seq2seq4repair_space>error:<seq2seq4repair_space>world<seq2seq4repair_space>must<seq2seq4repair_space>be<seq2seq4repair_space>of<seq2seq4repair_space>type<seq2seq4repair_space>BcelWorld" ) ; return false ; } ResolvedType current = m_world . resolve ( m_concreteAspect . name , true ) ; if ( ! ( current . isMissing ( ) ) ) { <START_BUG> reportError ( ( "Attempt<seq2seq4repair_space>to<seq2seq4repair_space>concretize<seq2seq4repair_space>but<seq2seq4repair_space>choosen<seq2seq4repair_space>aspect<seq2seq4repair_space>name<seq2seq4repair_space>already<seq2seq4repair_space>defined:<seq2seq4repair_space>" + ( stringify ( ) ) ) ) ; <END_BUG> return false ; } if ( ( ( m_concreteAspect . extend ) == null ) && ( ( m_concreteAspect . precedence ) != null ) ) { if ( m_concreteAspect . pointcuts . isEmpty ( ) ) { m_isValid = true ; m_perClause = new PerSingleton ( ) ; m_parent = null ; return true ; } else { reportError ( ( "Attempt<seq2seq4repair_space>to<seq2seq4repair_space>use<seq2seq4repair_space>nested<seq2seq4repair_space>pointcuts<seq2seq4repair_space>without<seq2seq4repair_space>extends<seq2seq4repair_space>clause:<seq2seq4repair_space>" + ( stringify ( ) ) ) ) ; return false ; } } m_parent = m_world . resolve ( m_concreteAspect . extend , true ) ; if ( m_parent . isMissing ( ) ) { String fixedName = m_concreteAspect . extend ; int hasDot = fixedName . lastIndexOf ( '.' ) ; while ( hasDot > 0 ) { char [ ] fixedNameChars = fixedName . toCharArray ( ) ; fixedNameChars [ hasDot ] = '$' ; fixedName = new String ( fixedNameChars ) ; hasDot = fixedName . lastIndexOf ( '.' ) ; m_parent = m_world . resolve ( UnresolvedType . forName ( fixedName ) , true ) ; if ( ! ( m_parent . isMissing ( ) ) ) { break ; } } } if ( m_parent . isMissing ( ) ) { reportError ( ( "Cannot<seq2seq4repair_space>find<seq2seq4repair_space>m_parent<seq2seq4repair_space>aspect<seq2seq4repair_space>for:<seq2seq4repair_space>" + ( stringify ( ) ) ) ) ; return false ; } if ( ! ( m_parent . isAbstract ( ) ) ) { reportError ( ( "Attempt<seq2seq4repair_space>to<seq2seq4repair_space>concretize<seq2seq4repair_space>a<seq2seq4repair_space>non-abstract<seq2seq4repair_space>aspect:<seq2seq4repair_space>" + ( stringify ( ) ) ) ) ; return false ; } if ( ! ( m_parent . isAspect ( ) ) ) { reportError ( ( "Attempt<seq2seq4repair_space>to<seq2seq4repair_space>concretize<seq2seq4repair_space>a<seq2seq4repair_space>non<seq2seq4repair_space>aspect:<seq2seq4repair_space>" + ( stringify ( ) ) ) ) ; return false ; } List elligibleAbstractions = new ArrayList ( ) ; Collection abstractMethods = getOutstandingAbstractMethods ( m_parent ) ; for ( Iterator iter = abstractMethods . iterator ( ) ; iter . hasNext ( ) ; ) { ResolvedMember method = ( ( ResolvedMember ) ( iter . next ( ) ) ) ; if ( "()V" . equals ( method . getSignature ( ) ) ) { String n = method . getName ( ) ; if ( n . startsWith ( "ajc$pointcut" ) ) { n = n . substring ( 14 ) ; n = n . substring ( 0 , n . indexOf ( "$" ) ) ; elligibleAbstractions . add ( n ) ; } else if ( hasPointcutAnnotation ( method ) ) { elligibleAbstractions . add ( method . getName ( ) ) ; } else { reportError ( ( ( ( "Abstract<seq2seq4repair_space>method<seq2seq4repair_space>'" + ( method . toString ( ) ) ) + "'<seq2seq4repair_space>cannot<seq2seq4repair_space>be<seq2seq4repair_space>concretized<seq2seq4repair_space>in<seq2seq4repair_space>XML:<seq2seq4repair_space>" ) + ( stringify ( ) ) ) ) ; return false ; } } else { if ( ( method . getName ( ) . startsWith ( "ajc$pointcut" ) ) || ( hasPointcutAnnotation ( method ) ) ) { reportError ( ( ( ( "Abstract<seq2seq4repair_space>method<seq2seq4repair_space>'" + ( method . toString ( ) ) ) + "'<seq2seq4repair_space>cannot<seq2seq4repair_space>be<seq2seq4repair_space>concretized<seq2seq4repair_space>as<seq2seq4repair_space>a<seq2seq4repair_space>pointcut<seq2seq4repair_space>(illegal<seq2seq4repair_space>signature,<seq2seq4repair_space>must<seq2seq4repair_space>have<seq2seq4repair_space>no<seq2seq4repair_space>arguments,<seq2seq4repair_space>must<seq2seq4repair_space>return<seq2seq4repair_space>void):<seq2seq4repair_space>" ) + ( stringify ( ) ) ) ) ; return false ; } else { reportError ( ( ( ( "Abstract<seq2seq4repair_space>method<seq2seq4repair_space>'" + ( method . toString ( ) ) ) + "'<seq2seq4repair_space>cannot<seq2seq4repair_space>be<seq2seq4repair_space>concretized<seq2seq4repair_space>in<seq2seq4repair_space>XML:<seq2seq4repair_space>" ) + ( stringify ( ) ) ) ) ; return false ; } } } List pointcutNames = new ArrayList ( ) ; for ( Iterator it = m_concreteAspect . pointcuts . iterator ( ) ; it . hasNext ( ) ; ) { Definition . Pointcut abstractPc = ( ( Definition . Pointcut ) ( it . next ( ) ) ) ; pointcutNames . add ( abstractPc . name ) ; } for ( Iterator it = elligibleAbstractions . iterator ( ) ; it . hasNext ( ) ; ) { String elligiblePc = ( ( String ) ( it . next ( ) ) ) ; if ( ! ( pointcutNames . contains ( elligiblePc ) ) ) { reportError ( ( ( ( "Abstract<seq2seq4repair_space>pointcut<seq2seq4repair_space>'" + elligiblePc ) + "'<seq2seq4repair_space>not<seq2seq4repair_space>configured:<seq2seq4repair_space>" ) + ( stringify ( ) ) ) ) ; return false ; } } m_perClause = m_parent . getPerClause ( ) ; m_isValid = true ; return m_isValid ; } private Collection getOutstandingAbstractMethods ( ResolvedType type ) { } private void getOutstandingAbstractMethodsHelper ( ResolvedType type , Map collector ) { } private String stringify ( ) { } private boolean hasPointcutAnnotation ( ResolvedMember member ) { } public byte [ ] getBytes ( ) { } private void reportError ( String message ) { } }

Fix:
reportError ( ( "Attempt<seq2seq4repair_space>to<seq2seq4repair_space>concretize<seq2seq4repair_space>but<seq2seq4repair_space>chosen<seq2seq4repair_space>aspect<seq2seq4repair_space>name<seq2seq4repair_space>already<seq2seq4repair_space>defined:<seq2seq4repair_space>" + ( stringify ( ) ) ) ) ;